1. Field of the Invention
The present invention relates to a cryopreservation container for freezing and preserving an animal cell.
2. Description of Related Art
Recently, animal cells have been used to produce various substances or to develop various medicines. To this end, it is necessary to preserve the animal cell to be used. The cellular life span is extremely short, and accordingly, the cell must be maintained by subcultivating the cell in a culture medium.
However, the culture condition depends on the kind of cell, and accordingly culturing is troublesome and takes a long time. Furthermore, a cross-substitution or a cross-penetration tends to occur between the cells, or the cell may be contaminated with a microorganism. Furthermore, a cell, having a characteristic to be easily degenerated must be preserved before degeneration starts. In particular, a gene-recombination type of animal cell aimed at a production of substances or hybridoma which bears an antibody or the like changes in property during culture, resulting in waste of valuable resources. The change in property must be checked when the cell is used.
It is known to use an ampoule or a tube in which the animal cell is enclosed together with a freezing culture medium to be frozen and preserved. As a freezing means can be used a deep freezer of about -80.degree. C. which is widely used in works or laboratories. Recently, liquid nitrogen has been used as a freezing means, since a good result can be obtained when an animal cell is preserved at as low temperature as possible below -100.degree. C. In this method of using liquid nitrogen, since it is not necessary to culture the cell, no degeneration of the cell occurs.
The animal cell must be frozen slowly rather than quickly, since quick freezing causes the cell to be extinguished or deactivated. If the ampoule or tube is directly put in the deep freezer or liquid nitrogen atmosphere, the animal cell enclosed in the ampoule or tube is quickly cooled, thus resulting in an extinction or deactivation of cell. As a matter of course, the extinct or deactivated animal cell is useless, so that the cryopreservation is meaningless.
The primary object of the present invention is to provide a cryopreservation container in which an animal cell can be slowly frozen in an existing deep freezer.